Is intramuscular (IM) diazepam useful?

From the Guidelines

Intramuscular (IM) diazepam is not a recommended route of administration due to its erratic absorption and unpredictable onset of action. When benzodiazepines are needed via the IM route, lorazepam (1-2 mg) is preferred as it has more reliable absorption and consistent effects 1. Diazepam IM injections can cause pain, tissue irritation, and sterile abscesses at the injection site. The drug is highly lipophilic and can precipitate in muscle tissue, leading to delayed and incomplete absorption.

In emergency situations requiring rapid anxiolysis or seizure control, intravenous diazepam (5-10 mg) is more effective, or if IV access is unavailable, rectal diazepam gel (0.2 mg/kg) or intranasal/buccal midazolam are better alternatives 1. Even for acute agitation, IM olanzapine (5-10 mg) or haloperidol (2-5 mg) with or without IM lorazepam would be more appropriate choices. The pharmacokinetic limitations of IM diazepam make it a poor choice when other routes of administration or alternative benzodiazepines are available.

Some key points to consider when evaluating the use of IM diazepam include:

• Erratic absorption and unpredictable onset of action
• Potential for pain, tissue irritation, and sterile abscesses at the injection site
• Preferential use of lorazepam (1-2 mg) via the IM route due to its more reliable absorption and consistent effects
• Availability of alternative routes of administration, such as intravenous or rectal, which may be more effective in emergency situations. It's also worth noting that midazolam has a more rapid onset of action and shorter duration of effect compared to diazepam, making it a preferred choice in certain situations 1.

From the FDA Drug Label

Diazepam is a useful adjunct for the relief of skeletal muscle spasm due to reflex spasm to local pathology (such as inflammation of the muscles or joints, or secondary to trauma); spasticity caused by upper motor neuron disorders (such as cerebral palsy and paraplegia); athetosis; stiff-man syndrome; and tetanus Diazepam Injection is a useful adjunct in status epilepticus and severe recurrent convulsive seizures. Diazepam is a useful premedication (the intramuscular route is preferred) for relief of anxiety and tension in patients who are to undergo surgical procedures.

Intramuscular (IM) diazepam is useful for:

• Relief of skeletal muscle spasm
• Status epilepticus and severe recurrent convulsive seizures
• Premedication for relief of anxiety and tension in patients undergoing surgical procedures
• Management of anxiety disorders or short-term relief of anxiety symptoms
• Symptomatic relief of acute agitation, tremor, impending or acute delirium tremens and hallucinosis in acute alcohol withdrawal 2
• Adjunctively prior to endoscopic procedures to diminish patient recall of the procedure 2
• Relief of anxiety and tension prior to cardioversion 2

From the Research

Intramuscular Diazepam Usefulness

• The usefulness of intramuscular (IM) diazepam can be evaluated based on its pharmacokinetics and efficacy in treating acute seizures 3.
• A study comparing IM diazepam administered via an autoinjector to rectal gel in healthy subjects found that the autoinjector resulted in slightly higher and less variable plasma concentrations of diazepam and its metabolite, desmethyldiazepam 3.
• The bioavailability of the diazepam autoinjector was approximately 14% higher than that of diazepam rectal gel, indicating that IM administration may be a viable alternative to rectal administration 3.
• Another study found that IM midazolam was effective in controlling acute seizures in children, with a faster onset of action compared to IV diazepam in patients without prior IV access 4.
• However, the study also noted that IM midazolam may not be as effective as IV diazepam in patients with prior IV access, highlighting the importance of considering individual patient factors when selecting a treatment route 4.

Efficacy in Acute Seizures

• IM diazepam has been shown to be effective in treating acute seizures, with a rapid onset of action and high bioavailability 3.
• A study evaluating the treatment of acute seizures with IM midazolam found that it was effective in controlling seizures in children, with a mean interval to cessation of convulsions of 97.22 seconds 4.
• The efficacy of IM diazepam in acute seizures is supported by its mechanism of action, which involves enhancing the activity of gamma-aminobutyric acid (GABA) in the brain, resulting in a calming effect on neuronal activity 5.

Comparison to Other Routes of Administration

• IM diazepam has been compared to other routes of administration, including rectal gel and IV diazepam, in terms of its pharmacokinetics and efficacy 3, 4.
• The results of these studies suggest that IM diazepam may be a viable alternative to rectal administration, with a faster onset of action and higher bioavailability 3.
• However, the choice of treatment route ultimately depends on individual patient factors, such as the presence of IV access and the severity of the seizure 4.